With electronic apparatus, such as smart phones, tablet personal computers (PCs), and notebook PCs, which are used in a state in which they are touching human hands or knees, an influence on the human body, such as burns, is apprehended when the surface temperature of the enclosures rises.
Formerly the following technique was proposed. Temperature is detected by a temperature sensor disposed on the surface of an enclosure of an electronic apparatus. When a detection result exceeds a threshold, control is exercised so as to lower the surface temperature.
See, for example, Japanese National Publications of International Patent Applications No. 2013-546214 and No. 2001-520741, and Japanese Laid-open Patent Publications No. 2011-010134, No. 2005-159317, No. 2000-252181, and No. 09-304195.
By the way, with electronic apparatus such as portable terminals disposing temperature sensors on the surfaces of the enclosures may mar the appearances. Therefore, a temperature sensor may be disposed on a substrate in an enclosure. In this case, a fixed value is subtracted from a measured value obtained by the temperature sensor. By doing so, the surface temperature of the enclosure is estimated.
With the method of subtracting the fixed value from the measured value obtained by the temperature sensor disposed on the substrate, however, an error between the actual surface temperature of the enclosure and a calculated surface temperature of the enclosure increases due to fluctuations in the temperature of a heat source.